Flexible seal assembly for spigot and bell conduit joint

ABSTRACT

A resilient sealing sleeve has one portion inserted in the end of the spigot member and the remaining portion, of larger outer diameter, extending into the bell portion of the joint. The interior wall of the sleeve has an annular recess to accommodate an annular pressure member which keeps the two portions of the sleeve pressed outwardly against the spigot and bell members respectively. The shoulder on the sleeve between the smaller and larger outer diameter portions is slotted to act as an air seal upon the development of vacuum within the conduit.

United States Patent Stout [451 A r. 18 1972 [54] FLEXIBLE SEAL ASSEMBLYFOR 2,719,348 10/1955 Desnos ..277/207 A SPIGOT AND BELL CONDUIT JOINT,2 ,1 7 12/19 5 Trnka [72] Inventor: John C. Stout, Portland, Oreg. p iExaminerTRoben smith [73] Assignee: Irrigation Accessories Co.,Portland, Oreg. Attorney-L Gesler [22] Filed: Dec. 11, 1970 {57]ABSTRACT [21] Appl. No.: 97,158 A resilient sealing sleeve has oneportion inserted in the end of the spigot member and the remainingportion, of larger outer diameter, extending into the bell portion ofthe joint. The in- ]i "277/207 285/ terior wall of the sleeve has anannular recess to accommodate [58] Fieid 1 an annular pressure memberwhich keeps the two portions of 5 5 the sleeve pressed outwardly againstthe spigot and bell members respectively. The shoulder on the sleevebetween the 5 6] References Cited smaller and larger outer diameterportions is slotted to act as an air seal upon the development of vacuumwithin the con- UNITED STATES PATENTS dult- 2,403,364 7/ 1946 l-lertzellet al ..277/207 A 6 Claims, 4 Drawing Figures PATENTEDAPR 18I972 3, 656,771

FIG. I

FIG. 4

INVENTOR I 5 ATTY'.

JOHN C. STOUT FLEXIBLE SEAL ASSEMBLY FOR SPIGOT AND BELL CONDUIT JOINTBACKGROUND OF THE INVENTION Various types of flexible and resilientseals have heretofore been developed for sealing the connection betweenthe members in a spigot and bell joint, but, as far as known, these havebeen designed for being inserted entirely, or largely, in between thespigot and the bell members, thus extending around the outside of thespigot on the inside of the bell and compressed in between the twomembers. Such seals have generally required specially formed ends eitherin the bell member or spigot member or in both for seating the seal andfor holding it in place, and also have necessitated the forming SUMMARYOF THE INVENTION The seal assembly includes a sleeve of rubber or othersuitable water-impervious, compressible, resilient material, havingapproximately one-half of its length formed with an outer diameter ofsuch size as to permit it to be-pressed into the end of the spigotmember of the two pipe ends forming the joint, and with the remainingportion formed with a sufficiently larger outer diameter so that it canbe pressed into the bell of the companion pipe end, thus causing the twoportions of the sleeve to have a sealing fit in the spigot and bellmembers respectively at the joint. To maintain a tight sealing pressureof the two portions of the sleeve against both the spigot end and theadjacent bell, without having to depend on any internal pressure withinthe pipeline, a cylindrical band or ring of metal or rigid plastic ispressed into the interior of the sealing sleeve. The inner wall of thesleeve is formed with a recess extending in from the bell end portion ofthe sleeve almost to the opposite end of the inner wall of the sleeve toreceive this cylindrical pressure band. The two ends of the sleevebeyond the ends of the pressure band are outwardly beveled to reduce theresistance of the sleeve to the flow in either direction in thepipeline. In order to prevent the possibility of any air seeping intothe joint from the outside by being sucked inbetween the bell member andthe engaging outer wall of the sleeve, in the event a vacuum shoulddevelop in the pipeline, the shoulder on the outer wall of the sleeve,marking the division between the smaller and larger outer diameterportions of the sleeve, is formed with an opposing V-shaped slot which,when engaged by air under pressure, will exert a tendency to open andthereby increase the pressure of the sleeve against the wall of the belland render the seal even more airtight at that point.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a sectional elevation of the sealing sleeve by itself, thesection being taken along the longitudinal center line;

FIG. 2 is a perspective view of the cylindrical pressure band by itself,drawn to a smaller scale;

FIG. 3 is a sectional elevation showing the sealing sleeve in place inthe end of the spigot member of a pipe joint and the pressure band inplace in the sleeve; and

FIG. 4 is a corresponding sectional elevation of the pipe joint and sealassembly with the bell member set in place over the sealing sleeve andthe spigot member.

The main sealing member of the assembly consists 4) a sleeve 10, shownbest in FIG. 1, of rubber or other compressible resilient materialsuitable for a flexible fluid-proof seal. The outer wall of the sleeveis formed with a generally smaller diameter surface portion 11 and agenerally larger diameter surface portion 12, with a shoulder 13separating these two portions. The smaller outer diameter portion 11 ofthe sleeve is designed to be pressed into the end of the spigot member14 (FIGS. 3 and 4) of the pipe joint, and the larger outer diameterportion 12 is designed to be pressed into the bell member 15 (FIG. ofthe pipe joint when the bell member is set in place over the spigotmember.

Preferably the smaller outer diameter portion 11 of the sleeve 10 isformed with the outer diameter increasing gradually toward thetermination of this end portion, which end portion is indicated at 1 1'in FIG. 1. The purpose of this is to aid in increasing the sealingpressure against the interior of the spigot at this end of the sleeve.

Preferably, also, the outer wall of the larger diameter portion 12 ofthe sleeve 10 is formed with a varying diameter causing this outer wallsection, when not pressed into the bell member, to assume the somewhatconcave formation shown at 12' in FIG. 1, to aid in increasing thesealing pressure against the bell member at each end of this largerouter diameter portion 12 of the sleeve.

The inside wall of the sealing sleeve 10 is formed with an annularrecess 16 (FIG. 1) extending in from the portion 12 of the sleeve andterminating at a flat annular ridge 17 a short distance from the otherend of the interior of the sleeve. The purpose of this annular recess 16is to provide a seat for a cylindrical pressure band 18 which is pressedinto the sleeve 10 after the sleeve is inserted into the spigot member14. The cylindrical pressure band 18 maintains a firm sealing pressureof the sleeve 10 against the wall of the spigot member 14, (and alsosimilarly against the engaged portion of the bell member 15, when thepipe joint is completely set up). Thus the sealing pressure of thesleeve against the interior of the spigot and bell members is notdependent upon the pressure otherwise present in the pipeline.

In place of the solid cylindrical pressure band 18 it would be possibleto use a spring band of plastic or metal to exert a constant outwardpressure in the sleeve 10. The solid cylindrical band or ring 18 asillustrated is considered preferable, but it is to be understood thateither may be employed in the carrying out of this invention.

The ends of the sleeve 10 are both beveled outwardly, as shown at 19 and20, to minimize the resistance offered by the sleeve to the flow throughthe pipeline in either direction.

Under certain conditions vacuum may develop within a pipeline, and insuch a situation there would be a tendency for air to be sucked into thepipeline through the joint, a condition which is undesirable. Any airsucked into the pipeline through the bell and spigot joint with thesleeve 10 mounted in place would have to leak in between the outersurface of the portion 12 of the sleeve and the surrounding wall of thebell member. To render even less likely the possibility of air beingdrawing in between these opposed surfaces and thus sucked into thepipeline through the spigot and bell joint, the wall of the shoulder 13of the sleeve 10 is provided with a substantially V- shaped slot 21(FIG. 1) forming a converging pair of lips which are normally broughttogether under the pressure of the sleeve portion 12 against the insidesurface of the bell member. However, should any strong inward suction ofair occur in between the spigot and surrounding end of the bell member,the pressure of the air against the shoulder 13 of the sleeve would thenhave a tendency to force the slot 21 open but this in turn would onlyincrease the pressure of the sleeve at the location of the outer lip ofthe slot against the confining wall of the bell and correspondinglyrender the seal between the sleeve and the bell still tighter at thispoint and render the passage of air therethrough even less possible.

As will be apparent, the entire sealing assembly is very simple inconstruction and is very quickly and easily mounted in place, theportion 11 of the sleeve 10 first being inserted in the spigot member,the pressure band 18 thus being placed in the sleeve, and finally thecompanion bell member being slid into position over the sleeve portion12 and the end of the spigot member. of the joint. Also, as previouslymentioned, this sealing assembly is specially designed to be used withordinary spigot and bell members, particularly in conduits and pipelinesof plastic, and with simple spigot and bell joint having minimumtelescoping tolerance. Theinvention eliminates the necessity ofrequiring any grooves to be provided in either member of the joint forseating a sealing ring or the necessity of providing any externalsealing clamps.

I claim:

1. in a conduit joint of the character described consisting of a spigotmember and a bell member encompassing the end of the spigot member, asealing assembly including a resilient, flexible sleeve extending fromthe interior of the spigot member into the bell member, the firstportion of said sleeve being of smaller outer diameter than theremaining second portion of said sleeve to enable said first portion tofit snugly -in said spigot member and to enable said second and largerdiameter portion to fit snugly in said bell member when the conduitjoint is put together, the inside wall of said sleeve having a recessand an internal member in said recess extending annularly around on theinterior of said sleeve and exerting outward pressure on said first andsaid second portions of said sleeve against said spigot and said bellmembers respectively.

2. The sealing assembly of claim 1 with said internal member consistingof a solid, cylindrical band pressed into said recess in said sleeve.

3. The sealing assembly of claim 2 with said recess extending in fromthe end of said sleeve in said bell member and terminating near theopposite end of said sleeve in said spigot member and an annularinternal ridge in said opposite end of said sleeve at the termination ofsaid cylindrical band, the radial thickness of said ridge correspondingapproximately to the radial thickness of said cylindrical band, and withthe ends of said sleeve beveled outwardly.

4. The sealing assembly of claim 1 with a shoulder on the outer wall ofsaid sleeve between said first and said second mentioned portions, andwith the outer diameter of said first mentioned portion increasingslightly from said shoulder to the termination of said first mentionedportion.

5. The sealing assembly of claim 1 with the outer diameter of saidsecond portion of said sleeve decreasing slightly from each end of saidsecond portion of said sleeve to the middle of said second portion toform a somewhat concave annular outer surface on said second portion ofsaid sleeve.

6. The sealing assembly of claim 1 with a shoulder on the outer wall ofsaid sleeve between said first and said second mentioned portions, andwith said shoulder provided with a slot having a top lip for increasingthe sealing pressure of said sleeve against said bell member in theevent of increased external air pressure being exerted against saidshoulder as the result of suction developing in the conduit and tendingto draw air into the conduit joint.

1. In a conduit joint of the character described consisting of a spigotmember and a bell member encompassing the end of the spigot member, asealing assembly including a resilient, flexible sleeve extending fromthe interior of the spigot member into the bell member, the firstportion of said sleeve being of smaller outer diameter than theremaining second portion of said sleeve to enable said first portion tofit snugly in said spigot member and to enable said second and largerdiameter portion to fit snugly in said bell member when the conduitjoint is put together, the inside wall of said sleeve having a recessand an internal member in said recess extending annularly around on theinterior of said sleeve and exerting outward pressure on said first andsaid second portions of said sleeve against said spigot and said bellmembers respectively.
 2. The sealing assembly of claim 1 with saidinternal member consisting of a solid, cylindrical band pressed intosaid recess in said sleeve.
 3. The sealing assembly of claim 2 with saidrecess extending in from the end of said sleeve in said bell member andterminating near the opposite end of said sleeve in said spigot memberand an annular internal ridge in said opposite end of said sleeve at thetermination of said cylindrical band, the radial thickness of said ridgecorresponding approximately to the radial thickness of said cylindricalband, and with the ends of said sleeve beveled outwardly.
 4. The sealingassembly of claim 1 with a shoulder on the outer wall of said sleevebetween said first and said second mentioned portions, and with theouter diameter of said first mentioned portion increasing slightly fromsaid shoulder to the termination of said first mentioned portion.
 5. Thesealing assembly of claim 1 with the outer diameter of said secondportion of said sleeve decreasing slightly from each end of said secondportion of said sleeve to the middle of said second portion to form asomewhat concave annular outer surface on said second portion of saidsleeve.
 6. The sealing assembly of claim 1 with a shoulder on the outerwall of said sleeve between said first and said second mentionedportIons, and with said shoulder provided with a slot having a top lipfor increasing the sealing pressure of said sleeve against said bellmember in the event of increased external air pressure being exertedagainst said shoulder as the result of suction developing in the conduitand tending to draw air into the conduit joint.